<template>
  <div class="file-upload">
    <div class="upload-area" :class="{ 'is-dragover': drag && isDragOver }" v-on="events">
      <slot v-if="isUploading" name="loading">
        <button disabled>正在上传</button>
      </slot>
      <slot name="uploaded" v-else-if="lastFileData && lastFileData.loaded" :uploadedData="lastFileData.data">
        <button>点击上传</button>
      </slot>
      <slot v-else name="default">
        <button>点击上传</button>
      </slot>
    </div>
    <input ref="fileInput" type="file" :style="{ display: 'none' }" @change="handleFileChange">
    <ul :class="`upload-list upload-list-${listType}`" v-if="showUploadList">
      <li :class="`uploaded-file upload-${file.status}`" v-for="file in filesList" :key="file.uid">
        <img v-if="file.url && listType === 'picture'" class="upload-list-thumbnail" :src="file.url" :alt="file.name">
        <span v-if="file.status === 'loading'" class="file-icon">
          <LoadingOutlined />
        </span>
        <span v-else class="file-icon">
          <FileOutlined />
        </span>
        <span class="filename">{{ file.name }}</span>
        <span class="delete-icon" @click="removeFile(file.uid)">
          <DeleteOutlined />
        </span>
      </li>
    </ul>
  </div>
</template>
<script lang="ts" setup>
import { reactive, ref, computed, type PropType } from 'vue'
import { DeleteOutlined, LoadingOutlined, FileOutlined } from '@ant-design/icons-vue'
import axios from 'axios'
import { v4 as uuidv4 } from 'uuid'
import { last } from 'lodash-es'
type UploadStaus = 'ready' | 'loading' | 'success' | 'error'
type FileListType = 'picture' | 'text'
type CheckUpload = (file: File) => boolean | Promise<File>
interface UploadFile {
  uid: string;
  size: number;
  name: string;
  status: UploadStaus;
  raw: File;
  resp?: any;
  url?: string;
}

defineOptions({
  name: 'Uploader'
})

const props = defineProps({
  action: {
    type: String,
    required: true
  },
  beforeUpload: {
    type: Function as PropType<CheckUpload>
  },
  drag: {
    type: Boolean,
    default: false
  },
  autoUpload: {
    type: Boolean,
    default: true
  },
  listType: {
    type: String as PropType<FileListType>,
    defualt: 'text'
  },
  showUploadList: {
    type: Boolean,
    default: true
  }
})
const emit = defineEmits(['success', 'error', 'change'])

const fileInput = ref<null | HTMLInputElement>(null)
const filesList = ref<UploadFile[]>([])
const isDragOver = ref(false)
const isUploading = computed(() => {
  return filesList.value.some(file => file.status === 'loading')
})
const lastFileData = computed(() => {
  const lastFile = last(filesList.value)
  if (lastFile) {
    return {
      loaded: lastFile.status === 'success',
      data: lastFile.resp
    }
  }
  return false
})
const removeFile = (id: string) => {
  filesList.value = filesList.value.filter(file => file.uid !== id)
}

const triggerUpload = () => {
  if (fileInput.value) {
    fileInput.value.click()
  }
}
const postFile = (readyFile: UploadFile) => {
  const formData = new FormData()
  formData.append(readyFile.name, readyFile.raw)
  readyFile.status = 'loading'
  axios.post(props.action, formData, {
    headers: {
      'Content-Type': 'multipart/form-data'
    }
  }).then(resp => {
    readyFile.status = 'success'
    readyFile.resp = resp.data
    emit('success', { resp: resp.data, file: readyFile, list: filesList.value })
  }).catch((e: any) => {
    readyFile.status = 'error'
    emit('error', { error: e, file: readyFile, list: filesList.value })
  }).finally(() => {
    if (fileInput.value) {
      fileInput.value.value = ''
    }
  })
}
// addFileToList
const addFileToList = (uploadedFile: File) => {
  const fileObj = reactive<UploadFile>({
    uid: uuidv4(),
    size: uploadedFile.size,
    name: uploadedFile.name,
    status: 'ready',
    raw: uploadedFile
  })
  if (props.listType === 'picture') {
    try {
      fileObj.url = URL.createObjectURL(uploadedFile)
    } catch (err) {
      console.error('upload File error', err)
    }
    // FileReader to preview local image
    // const fileReader = new FileReader()
    // fileReader.readAsDataURL(uploadedFile)
    // fileReader.addEventListener('load', () => {
    //   fileObj.url = fileReader.result as string
    // })
  }
  filesList.value.push(fileObj)
  if (props.autoUpload) {
    postFile(fileObj)
  }
}
const beforeUploadCheck = (files: null | FileList) => {
  if (files) {
    const uploadedFile = files[0]
    if (props.beforeUpload) {
      const result = props.beforeUpload(uploadedFile)
      if (result && result instanceof Promise) {
        result.then(processedFile => {
          if (processedFile instanceof File) {
            addFileToList(processedFile)
          } else {
            throw new Error('beforeUpload Promise should return File object')
          }
        }).catch(e => {
          console.error(e)
        })
      } else if (result === true) {
        addFileToList(uploadedFile)
      }
    } else {
      addFileToList(uploadedFile)
    }
  }
}
const uploadFiles = () => {
  filesList.value.filter(file => file.status === 'ready').forEach(readyFile => postFile(readyFile))
}

let events: { [key: string]: (e: any) => void } = {
  'click': triggerUpload
}
const handleFileChange = (e: Event) => {
  const target = e.target as HTMLInputElement
  beforeUploadCheck(target.files)
}
const handleDrag = (e: DragEvent, over: boolean) => {
  e.preventDefault()
  isDragOver.value = over
}
const handleDrop = (e: DragEvent) => {
  e.preventDefault()
  isDragOver.value = false
  if (e.dataTransfer) {
    beforeUploadCheck(e.dataTransfer.files)
  }
}
if (props.drag) {
  events = {
    ...events,
    'dragover': (e: DragEvent) => { handleDrag(e, true) },
    'dragleave': (e: DragEvent) => { handleDrag(e, false) },
    'drop': handleDrop
  }
}
</script>
<style lang="scss">
.upload-list {
  margin: 0;
  padding: 0;
  list-style-type: none;
}

.upload-list li {
  transition: all .5s cubic-bezier(.55, 0, .1, 1);
  font-size: 14px;
  line-height: 1.8;
  margin-top: 5px;
  box-sizing: border-box;
  border-radius: 4px;
  min-width: 200px;
  position: relative;

  &:first-child {
    margin-top: 10px;
  }

  .upload-list-thumbnail {
    vertical-align: middle;
    display: inline-block;
    width: 70px;
    height: 70px;
    position: relative;
    z-index: 1;
    background-color: #fff;
    object-fit: cover;
  }

  .file-icon {
    svg {
      margin-right: 5px;
      color: rgba(0, 0, 0, 0.45);
    }
  }

  .filename {
    margin-left: 5px;
    margin-right: 40px;
  }

  &.upload-error {
    color: #f5222d;

    svg {
      color: #f5222d;
    }
  }

  .file-status {
    display: block;
    position: absolute;
    right: 5px;
    top: 0;
    line-height: inherit;
  }

  .delete-icon {
    display: none;
    position: absolute;
    right: 7px;
    top: 0;
    line-height: inherit;
    cursor: pointer;
  }

  &:hover {
    background-color: #efefef;

    .file-status {
      display: none;
    }

    .delete-icon {
      display: block;
    }
  }
}
</style>
